Central Pneumatic 99792 Installation manual

HEAVY-DUTY
AIR CHIPPING HAMMER
99792
SET UP AND OPERATING INSTRUCTIONS
Distributed exclusively by Harbor Freight Tools®.
3491 Mission Oaks Blvd., Camarillo, CA 93011
Visit our website at: http://www.harborfreight.com
Read this material before using this product.
Failure to do so can result in serious injury.
SAVE THIS MANUAL.
Copyright©2008 by Harbor Freight Tools®. All rights reserved. No portion of this manual or any artwork
contained herein may be reproduced in any shape or form without the express written consent of
Harbor Freight Tools. Diagrams within this manual may not be drawn proportionally. Due to continuing
improvements, actual product may differ slightly from the product described herein. Tools required for
assembly and service may not be included.
For technical questions or replacement parts, please call 1-800-444-3353.
Manual Revised 11h

SKU 99792 For technical questions, please call 1-800-444-3353. Page 2
CONTENTS
SAFETY ALERT SYMBOL AND
SIGNAL WORDS .............................3
IMPORTANT SAFETY
INSTRUCTIONS .......................... 3
GENERAL...........................................3
WORK AREA......................................3
PERSONAL SAFETY .........................4
TOOL USE AND CARE ...................... 4
SERVICE ............................................5
AIR SOURCE......................................5
SYMBOLS AND SPECIFIC
SAFETY INSTRUCTIONS ........... 5
SYMBOL DEFINITIONS .....................5
SPECIFIC SAFETY INSTRUCTIONS 6
VIBRATION PRECAUTIONS ........ 7
FUNCTIONAL DESCRIPTION....... 8
SPECIFICATIONS ..............................8
INITIAL TOOL SET UP/
ASSEMBLY.................................. 8
UNPACKING.......................................8
AIR SUPPLY.......................................8
INSTALLING A CHISEL .....................9
WORK PIECE AND WORK AREA
SET UP .......................................... 11
GENERAL OPERATING
INSTRUCTIONS ............................ 11
CHIPPING IN A STRAIGHT
LINE:.........................................12
BREAKING UP CONCRETE: ..... 12
USER-MAINTENANCE
INSTRUCTIONS ........................ 13
CLEANING, MAINTENANCE, AND
LUBRICATION...............................13
TROUBLESHOOTING......................14
PARTS LIST................................. 15
ASSEMBLY DIAGRAM................ 16
LIMITED 1 YEAR WARRANTY ... 17

SKU 99792 For technical questions, please call 1-800-444-3353. Page 3
SAVE THIS MANUAL
Keep this manual for the safety warn-
ings and precautions, assembly, operat-
ing, inspection, maintenance and cleaning
procedures. Write the product’s serial
number in the back of the manual near the
assembly diagram (or month and year of
purchase if product has no number). Keep
this manual and the receipt in a safe and
dry place for future reference.
Safety Alert Symbol and Signal
Words
In this manual, on the labeling,
and all other information provid-
ed with this product:
This is the safety alert
symbol. It is used to alert
you to potential personal
injury hazards. Obey all
safety messages that
follow this symbol to avoid
possible injury or death.
DANGER indicates
a hazardous
situation which, if not
avoided, will result in death or
serious injury.
WARNING
indicates a
hazardous situation which, if
not avoided, could result in
death or serious injury.
CAUTION, used
with the safety
alert symbol, indicates a
hazardous situation which, if
not avoided, could result in
minor or moderate injury.
NOTICE is used to
address practices
not related to personal injury.
CAUTION, without
the safety alert
symbol, is used to address
practices not related to
personal injury.
IMPORTANT SAFETY
INSTRUCTIONS
INSTRUCTIONS PERTAINING
TO A RISK OF FIRE,
ELECTRIC SHOCK, OR
INJURY TO PERSONS
WARNING – When using tools, basic pre-
cautions should always be followed,
including the following:
General
a. To reduce the risks of electric
shock, re, and injury to persons,
read all the instructions before us-
ing the tool.
Work area
a. Keep the work area clean and well
lighted. Cluttered benches and dark
areas increase the risks of electric
shock, re, and injury to persons.
b. Do not operate the tool in explo-
sive atmospheres, such as in the
presence of ammable liquids,
gases, or dust. The tool is able to
create sparks resulting in the ignition
of the dust or fumes.
c. Keep bystanders, children, and
visitors away while operating the

SKU 99792 For technical questions, please call 1-800-444-3353. Page 4
tool. Distractions are able to result in
the loss of control of the tool.
Personal safety
a. Stay alert. Watch what you are do-
ing and use common sense when
operating the tool. Do not use the
tool while tired or under the inu-
ence of drugs, alcohol, or medica-
tion. A moment of inattention while
operating the tool increases the risk
of injury to persons.
b. Dress properly. Do not wear loose
clothing or jewelry. Contain long
hair. Keep hair, clothing, and
gloves away from moving parts.
Loose clothes, jewelry, or long hair
increases the risk of injury to persons
as a result of being caught in moving
parts.
c. Avoid unintentional starting. Be
sure the switch is off before con-
necting to the air supply. Do not
carry the tool with your nger on the
switch or connect the tool to the air
supply with the switch on.
d. Remove adjusting keys and
wrenches before turning the tool
on. A wrench or a key that is left at-
tached to a rotating part of the tool
increases the risk of personal injury.
e. Do not overreach. Keep proper
footing and balance at all times.
Proper footing and balance enables
better control of the tool in unexpect-
ed situations.
f. Use safety equipment. A
dust mask, non-skid safety
shoes and a hard hat must
be used for the applicable
conditions. Wear heavy-duty work
gloves during use.
g. Always wear eye protec-
tion. Wear ANSI-ap-
proved safety goggles.
h. Always wear hearing
protection when using
the tool. Prolonged expo-
sure to high intensity noise
is able to cause hearing loss.
a. DANGER! Keep hands and body
away from cutting area and chisel.
Keep your second hand on aux-
iliary handle or motor housing.
Contact with the chisel could result in
serious injury.
b. Explore the workarea to avoid
contact with hidden wiring or pip-
ing. Thoroughly inspect the workarea
for possible hidden wiring or piping
before performing work. Contact with
live wiring will shock the operator.
Tool use and care
a. Use clamps or another practical
way to secure and support the
workpiece to a stable platform.
Holding the work by hand or against
the body is unstable and is able to
lead to loss of control.
b. Do not force the tool. Use the
correct tool for the application. The
correct tool will do the job better and
safer at the rate for which the tool is
designed.
c. Do not use the tool if the switch
does not turn the tool on or off.
Any tool that cannot be controlled
with the switch is dangerous and
must be repaired.

SKU 99792 For technical questions, please call 1-800-444-3353. Page 5
d. Disconnect the tool from the air
source before making any adjust-
ments, changing accessories, or
storing the tool. Such preventive
safety measures reduce the risk of
starting the tool unintentionally. Turn
off and detach the air supply, safely
discharge any residual air pressure,
and release the throttle and/or turn
the switch to its off position before
leaving the work area.
e. Store the tool when it is idle out of
reach of children and other un-
trained persons. A tool is dangerous
in the hands of untrained users.
f. Maintain the tool with care. Keep a
cutting tool sharp and clean. A prop-
erly maintained tool, with sharp cut-
ting edges reduces the risk of binding
and is easier to control.
g. Check for misalignment or bind-
ing of moving parts, breakage of
parts, and any other condition that
affects the tool’s operation. If dam-
aged, have the tool serviced before
using. Many accidents are caused
by poorly maintained tools. There is a
risk of bursting if the tool is damaged.
h. Use only accessories that are
identied by the manufacturer for
the specic tool model. Use of an
accessory not intended for use with
the specic tool model, increases the
risk of injury to persons.
Service
a. Tool service must be performed
only by qualied repair personnel.
b. When servicing a tool, use only
identical replacement parts. Use
only authorized parts.
c. Use only the lubricants supplied
with the tool or specied by the
manufacturer.
Air source
a. Never connect to an air
source that is capable of
exceeding 90 psi. Over
pressurizing the tool may
cause bursting, abnormal operation,
breakage of the tool or serious injury
to persons. Use only clean, dry,
regulated compressed air at the rated
pressure or within the rated pressure
range as marked on the tool. Always
verify prior to using the tool that the
air source has been adjusted to the
rated air pressure or within the rated
air-pressure range.
b. Never use oxygen, carbon dioxide,
combustible gases or any bottled
gas as an air source for the tool.
Such gases are capable of explosion
and serious injury to persons.
SAVE THESE
INSTRUCTIONS.
SYMBOLS AND
SPECIFIC SAFETY
INSTRUCTIONS
Symbol Denitions
Symbol Property or statement
noNo-load speed
.../min Revolutions or reciprocation per
minute
PSI Pounds per square inch of pressure
Chart continued in next column.

SKU 99792 For technical questions, please call 1-800-444-3353. Page 6
Symbol Denitions
Symbol Property or statement
ft-lb Foot-pounds of torque
BPM Blows per minute
CFM Cubic Feet per Minute ow
SCFM Cubic Feet per Minute ow at
standard conditions
NPT National pipe thread, tapered
NPS National pipe thread, straight
WARNING marking concerning Risk
of Eye Injury. Wear ANSI-approved
eye protection.
WARNING marking concerning Risk
of Hearing Loss. Wear hearing
protection.
WARNING marking concerning Risk
of Respiratory Injury. Wear NIOSH-
approved dust mask/respirator.
WARNING marking concerning Risk
of Explosion.
Specic Safety Instructions
1. Always disconnect tool from its com-
pressed air supply source before per-
forming any services or maintenance,
Such as cleaning the tool, moving to
a different work location, handing the
tool to another person, etc.
Caution: After disconnecting the TOOL
from the air compressor, the TOOL
may still be pressurized. Point the
TOOL onto an extra piece of work
surface and depress the trigger until
all pressure is released. Also:
a. Never use combustible gas as a
power source.
b. Never operate this tool at greater
than 90 PSI operating pressure.
Warning: People with pacemakers should
consult their physician(s) before us-
ing this product; operation of equip-
ment in close proximity to a heart
pacemaker could cause interference
or failure of the pacemaker.
2. Your risk from these exposures var-
ies, depending on how often you
do this type of work. To reduce your
exposure to these chemicals: work in
a well ventilated area, and work with
approved safety equipment, such as
those dust masks that are specially
designed to lter out microscopic
particles.
3. The warnings and precautions dis-
cussed in this manual cannot cover
all possible conditions and situations
that may occur. It must be under-
stood by the operator that common
sense and caution are factors which
cannot be built into this product, but
must be supplied by the operator.
4. WARNING: Some dust created by
power sanding, sawing, grinding, drill-
ing, and other construction activities,
contains chemicals known [to the
State of California] to cause cancer,
birth defects or other reproductive
harm. Some examples of these
chemicals are:
• Lead from lead-based paints
• Crystalline silica from bricks and
cement or other masonry products
• Arsenic and chromium from chemi-
cally treated lumber
Your risk from these exposures var-
ies, depending on how often you do
this type of work. To reduce your
exposure to these chemicals: work in

SKU 99792 For technical questions, please call 1-800-444-3353. Page 7
a well ventilated area, and work with
approved safety equipment, such as
those dust masks that are specially
designed to lter out microscopic
particles. (California Health & Safety
Code § 25249.5, et seq.)
WARNING: The brass components
of this product contain lead, a chemi-
cal known to the State of California
to cause birth defects (or other repro-
ductive harm). (California Health &
Safety code § 25249.5, et seq.)
5. Only use with accessories rated to
handle the forces exerted by this tool
during operation. Other accessories
not designed for the forces gener-
ated may break and forcefully launch
pieces.
6. Attach all accessories properly to the
tool before connecting the air sup-
ply. A loose accessory may detach or
break during operation.
7. Obey the manual for the air compres-
sor used to power this tool.
8. Install an in-line shutoff valve to allow
immediate control over the air supply
in an emergency, even if a hose is
ruptured.
9. Use this tool with both hands only.
Using tools with only one hand can
result in loss of control.
10. Do not lay the tool down until it has
come to a complete stop. Moving
parts can grab the surface and pull
the tool out of your control.
Vibration Precautions
This tool vibrates during use. Re-
peated or long-term exposure to vibra-
tion may cause temporary or permanent
physical injury, particularly to the hands,
arms and shoulders. To reduce the risk of
vibration-related injury:
1. Anyone using vibrating tools regu-
larly or for an extended period should
rst be examined by a doctor and
then have regular medical check-
ups to ensure medical problems are
not being caused or worsened from
use. Pregnant women or people
who have impaired blood circulation
to the hand, past hand injuries, ner-
vous system disorders, diabetes, or
Raynaud’s Disease should not use
this tool. If you feel any medical or
physical symptoms related to vibra-
tion (such as tingling, numbness, and
white or blue ngers), seek medical
advice as soon as possible.
2. Do not smoke during use. Nico-
tine reduces the blood supply to the
hands and ngers, increasing the risk
of vibration-related injury.
3. Wear suitable gloves to reduce the
vibration effects on the user.
4. Use tools with the lowest vibration
when there is a choice between dif-
ferent processes.
5. Include vibration-free periods each
work day.
6. Grip tool as lightly as possible (while
still keeping safe control of it). Let
the tool do the work.
7. To reduce vibration, maintain tool as
explained in this manual. If abnormal
vibration occurs, stop immediately.
SAVE THESE
INSTRUCTIONS.

SKU 99792 For technical questions, please call 1-800-444-3353. Page 8
FUNCTIONAL DESCRIPTION
Specications
Chipping Rate 1800 Blows per Minute
Chisel Shank Diameter 11/16"
Operating Pressure 90 PSI
Air Inlet 3/8" - 18 NPT
Air Consumption 20 CFM (Continuous)
10 CFM (Intermittent)
Overall Length 17"
Net Weight 17.5Lbs
* Maximum speed at stated maximum air pressure. Ex-
cess air pressure is hazardous and may cause the tool
to exceed stated maximum speed.
INITIAL TOOL SET UP/
ASSEMBLY
Read the ENTIRE IMPORTANT
SAFETY INFORMATION
section at the beginning of this
manual including all text under
subheadings therein before set
up or use of this product.
Note: For additional information regarding
the parts listed in the following pages,
refer to the Assembly Diagram near
the end of this manual.
Unpacking
When unpacking, make sure that
the item is intact and undamaged. If any
parts are missing or broken, please call
Harbor Freight Tools at the number shown
throughout the manual as soon as pos-
sible.
• This air tool may be shipped with a
protective plug covering the air inlet.
Remove this plug before set up.
Air Supply
TO PREVENT
EXPLOSION:
Use only clean, dry, regulated,
compressed air to power this
tool. Do not use oxygen,
carbon dioxide, combustible
gases, or any other bottled gas
as a power source for this tool.
1. Incorporate an in-line oiler, shut-off
valve, regulator with pressure gauge,
and lter for best service, as shown in
the diagram above. An in-line shut-
off valve is an important safety
device because it controls the air
supply even if the air hose is rup-
tured.
Note: If an automatic oiler system is not
used, add a few drops of Pneumatic
Tool Oil to the airline connection be-
fore operation. Add a few more drops
after each hour of continual use.
2. Attach an air hose to the compres-
sor’s air outlet. Connect the air hose
to the air inlet of the tool. Other com-
ponents, such as a connector and

SKU 99792 For technical questions, please call 1-800-444-3353. Page 9
quick coupler, will make operation
more efcient, but are not required.
WARNING! TO PREVENT SERIOUS
INJURY FROM ACCIDENTAL
OPERATION:
Do not install a female quick
coupler on the tool. Such a coupler
contains an air valve that will allow
the air tool to retain pressure and
operate accidentally after the air
supply is disconnected.
Note: Air ow, and therefore tool perfor-
mance, can be hindered by under-
sized air supply components.
3. The air hose must be long enough
to reach the work area with enough
extra length to allow free movement
while working.
4. Make sure the tool’s throttle or switch
is in the off position; refer to Opera-
tion section for description of con-
trols.
5. Close the in-line safety valve be-
tween the compressor and the tool.
6. Turn on the air compressor according
to the manufacturer’s directions and
allow it to build up pressure until it
cycles off.
7. Adjust the air compressor’s output
regulator so that the air output is
enough to properly power the tool,
but the output shall not exceed the
tool’s maximum air pressure at any
time. Adjust the pressure gradually,
while checking the air output gauge
to set the right pressure value.
8. Inspect the air connections for leaks.
Repair any leaks found.
9. If the tool will not be used at this
time, turn off and detach the air sup-
ply, safely discharge any residual air
pressure, and release the throttle
and/or turn the compressor switch to
its off position to prevent accidental
operation.
Installing a Chisel
Note: All part numbers refer to the As-
sembly Diagram and Parts List on
Pages 16 and 17.
1.
Fig. 1
To install a Chisel (not included but
are offered exclusively from Harbor
Freight Tools), rst determine which
type of Chisel is appropriate for job at
hand.
a. For chipping in straight lines, you
should use a Flat Tip Chisel.
b. For breaking up concrete, use a
Pointed Tip Chisel.
2. As shown (see Fig. 1), using a wire or
screw driver or simply your ngers to

SKU 99792 For technical questions, please call 1-800-444-3353. Page 10
pull out the Lockcoil Spring (17) from
the Retaining Sleeve (16). This spring
is designed as a locking device. Then
remove the Retaining Sleeve (16)
from the hammer.
3.
Fig. 2
Put the spring aside. Lubricate the
top edge of the chisel shank chamfer
with oil or light grease and then insert
the chisel from the ellipse opening of
the Retaining Sleeve (16). (See Fig.
2.)
4. During usage, the Retaining Sleeve
(16) ledge may be slightly elongated,
preventing insertion of the chisel into
the Retaining Sleeve. It may require
some force to get the Chisel’s lobes
past this point and to slide into the
chisel mounting channel.
5.
Fig. 3
Turn the chisel 90º and let the ange
of the chisel rest on the bottom of the
ellipse slot as shown. (See Fig. 3.).
6.
Fig. 4
Align the chisel shank to the hole on
the hammer’s Cylinder (18) and at-
tach the Chisel and Retaining Sleeve
to the hammer body as shown. (See
Fig. 4.)
7. There is an O-Ring (9) inside the
channel about half way down. The
chisel may stop here. Apply a little
more force to push the chisel past the
O-ring, and into the channel.

SKU 99792 For technical questions, please call 1-800-444-3353. Page 11
8.
Fig. 5
Re-insert the Lockcoil Spring (17) all
the way into the slot on the sleeve
with only the triangular wire ring left
outside (see Fig. 5). Pull on the chisel
vigorously to make sure the chisel
is securely locked into the Retain-
ing Sleeve (16) before attaching the
Chipper Hammer to an air source.
Read the ENTIRE IMPORTANT
SAFETY INFORMATION
section at the beginning of this
manual including all text under
subheadings therein before set
up or use of this product.
Inspect tool before use, looking
for damaged, loose, and
missing parts. If any problems
are found, do not use tool until
repaired.
Work Piece and Work Area Set Up
1. Designate a work area that is clean
and well-lit. The work area must not
allow access by spectators, children
or pets to prevent injury and distrac-
tion.
2. Route the air hose along a safe route
to reach the work area without creat-
ing a tripping hazard or exposing the
air hose to possible damage. The air
hose must be long enough to reach
the work area with enough extra
length to allow free movement while
working.
3. There must not be hazardous ob-
jects (such as utility lines or foreign
objects) nearby that will present a
hazard while working.
General Operating Instructions
1. If an automatic oiler is not used, add
a few drops of Pneumatic Tool Oil
to the airline connection before use.
Add a few drops more after each
hour of continual use.
2. Always wear ANSI-approved safety
goggles and full face shield, dust
mask along with ear protection when
operating the Chipping Hammer.
3. Be aware of ying concrete chips.
Keep all spectators clear of the work
area.
4. Do not operate this tool if you have
back, neck, wrist or other conditions
or injuries that will be aggravated by
the severe jerking forces that this tool
exerts upon its operator.
5. Use the weight of the Chipping Ham-
mer to your advantage while breaking
up concrete. Keep the tool in a verti-
cal position whenever possible.
Warning: If the Chipping Hammer should
ever gets out of control, release the
Throttle Lever immediately.
Note: This tool is intended to break up
larger pieces of concrete only.

SKU 99792 For technical questions, please call 1-800-444-3353. Page 12
Chipping in a Straight line:
1. Use chalk or some other suitable
writing material, mark your work
surface to delineate the area you
intend to chip.
2. Once the Hammer is attached to the
Air Compressor as described in the
instructions, place the Chisel along
one of the marked lines. Hold the
Chipping Hammer rmly with both
hands.
3. To begin chipping, depress the
Throttle Lever (6) with your thumb.
4. As the Chipping Hammer breaks
through the top layer of concrete,
press down on the Chipping Hammer
to break up the sections below the
surface as well.
5. Keep moving the Chipping Hammer
along the line you want to section,
breaking the concrete as you go.
If the Chipping Hammer jumps out
of the designated area, release the
Throttle Lever and reposition the
Chisel back inside the line.
6. Continue to chip the concrete along
the marked line until the entire area
has been sectioned.
7. When done chipping, release the
Throttle Lever and allow the tool to
stop.
Breaking up Concrete:
1. Place the Bit on the center of the
piece of concrete. Hold the Chipping
Hammer rmly with both hands.
2. Depress the Throttle Lever with
your thumb to activate the Chipping
Hammer.
3. As the chipping action begins to
break the chunks of concrete,
release the Throttle Lever to stop the
Chipping Hammer, and reposition
the Chisel on larger pieces. Do not
attempt to break up small pieces with
this tool; the chipping rate of 1800
blows per minute is too aggressive
for breaking up small pieces of
concrete.
4. If the tool requires more force to
accomplish the task, verify that the
tool receives sufcient, unobstructed
airow (CFM) and increase the
pressure (PSI) output of the regulator
up to the maximum air pressure
rating of this tool.
CAUTION! TO PREVENT TOOL
AND ACCESSORY FAILURE,
RESULTING IN INJURY:
Do not exceed the tool’s maximum
air pressure rating.
If the tool still does not have sufcient
force at maximum pressure and
airow, then a larger tool may be
required.
5. To prevent accidents, turn off the
tool, detach the air supply, safely
discharge any residual air pressure
in the tool. Wipe external surfaces
of the tool with clean, dry cloth, and
apply a thin coat of tool oil. Then
store the tool indoors out of children’s
reach.

SKU 99792 For technical questions, please call 1-800-444-3353. Page 13
USER-MAINTENANCE
INSTRUCTIONS
Procedures not specically
explained in this manual
must be performed only by a
qualied technician.
TO PREVENT
SERIOUS INJURY
FROM ACCIDENTAL
OPERATION:
Turn off the tool, detach the
air supply, safely discharge
any residual air pressure in
the tool, and release the
throttle and/or turn the switch
to its off position before
performing any inspection,
maintenance, or cleaning
procedures.
TO PREVENT SERIOUS
INJURY FROM TOOL
FAILURE:
Do not use damaged
equipment. If abnormal
noise, vibration, or leaking
air occurs, have the problem
corrected before further use.
TO PREVENT EXPLOSION:
Lubricate the tool only
with specied lubricants.
Lubricate the air inlet
using only pneumatic tool
oil. Lubricate the internal
mechanism using only
white lithium grease. Other
lubricants may damage the
mechanism and may be
highly ammable, causing an
explosion.
Cleaning, Maintenance, and
Lubrication
Note: Your Chipping Hammer will perform
best and require minimal mainte-
nance when connected to an Airline
Oiler as shown on Page 8. If you do
not use an Airline Oiler, follow the
routine maintenance steps below.
Note: These procedures are in addition to
the regular checks and maintenance
explained as part of the regular op-
eration of the air-operated tool.
1. Chisels designed specically to be
used with this product are sold exclu-
sively through Harbor Freight Tools.
2. Daily - Air Supply Maintenance:
Every day, perform maintenance on
the air supply according to the com-
ponent manufacturers’ instructions.
The lubricator’s oil level needs to be
maintained and the moisture lter
must be regularly drained. Perform-
ing routine maintenance on the air
supply will allow the tool to operate
more safely and will also reduce wear
on the tool.
3. Quarterly (every 3 months) - Tool
Disassembly, Cleaning, and In-
spection:
Have the internal mechanism
cleaned, inspected, and lubricated by
a qualied technician.

SKU 99792 For technical questions, please call 1-800-444-3353. Page 14
Troubleshooting
Problem Possible Causes Likely Solutions
Decreased output.
1. Not enough air pressure and/
or air ow.
2. Obstructed trigger.
3. Incorrect lubrication or not
enough lubrication.
4. Blocked air inlet screen (if
equipped).
5. Air leaking from loose housing.
6. Mechanism contaminated.
7. Chisel edge is damaged.
1. Check for loose connections and make sure
that air supply is providing enough air ow
(CFM) at required pressure (PSI) to the
tool’s air inlet. Do not exceed maximum air
pressure.
2. Clean around trigger to ensure free
movement.
3. Lubricate using air tool oil and grease
according to directions.
4. Clean air inlet screen of buildup.
5. Make sure housing is properly assembled
and tight.
6. Have qualied technician clean and lubricate
mechanism. Install in-line lter in air supply
as stated in Initial Set Up: Air Supply.
7. Replace with a new chisel do not sharpen.
Housing heats
during use.
1. Incorrect lubrication or not
enough lubrication.
2. Worn parts.
1. Lubricate using air tool oil and grease
according to directions.
2. Have qualied technician inspect internal
mechanism and replace parts as needed.
Severe air
leakage.
(Slight air leakage
is normal,
especially on older
tools.)
1. Cross-threaded housing
components.
2. Loose housing.
3. Damaged valve or housing.
4. Dirty, worn or damaged valve.
1. Check for incorrect alignment and uneven
gaps. If cross-threaded, disassemble and
replace damaged parts before use.
2. Tighten housing assembly. If housing cannot
tighten properly, internal parts may be
misaligned.
3. Replace damaged components.
4. Clean or replace valve assembly.
Follow all safety precautions whenever diagnosing or servicing the
tool. Disconnect air supply before service.

SKU 99792 For technical questions, please call 1-800-444-3353. Page 15
PLEASE READ THE FOLLOWING
CAREFULLY
THE MANUFACTURER AND/OR DISTRIBUTOR
HAS PROVIDED THE PARTS LIST AND
ASSEMBLY DIAGRAM IN THIS MANUAL AS
A REFERENCE TOOL ONLY. NEITHER THE
MANUFACTURER OR DISTRIBUTOR MAKES
ANY REPRESENTATION OR WARRANTY OF
ANY KIND TO THE BUYER THAT HE OR SHE
IS QUALIFIED TO MAKE ANY REPAIRS TO THE
PRODUCT, OR THAT HE OR SHE IS QUALIFIED
TO REPLACE ANY PARTS OF THE PRODUCT.
IN FACT, THE MANUFACTURER AND/OR
DISTRIBUTOR EXPRESSLY STATES THAT
ALL REPAIRS AND PARTS REPLACEMENTS
SHOULD BE UNDERTAKEN BY CERTIFIED
AND LICENSED TECHNICIANS, AND NOT BY
THE BUYER. THE BUYER ASSUMES ALL RISK
AND LIABILITY ARISING OUT OF HIS OR HER
REPAIRS TO THE ORIGINAL PRODUCT OR
REPLACEMENT PARTS THERETO, OR ARISING
OUT OF HIS OR HER INSTALLATION OF
REPLACEMENT PARTS THERETO.
PARTS LIST
Part Description Qty
1 Throttle Valve Plug
2 Bushing
3 Throttle Valve
4 Valve Spring
5 Throttle Valve Base
6 Throttle Lever
7 Upper Valve Case Lid
8 Valve
9 O-Ring
10 Handle
11 Lower Valve Case Lid
12 Dowel Pin
13 Piston
14 Lock
15 O-Ring
16 Retaining Sleeve
17 Lockcoil Spring
18 Cylinder
19 Permanent Bushing
20 Screen Retainer
21 Lock Shield
22 Mesh Screen
23 Throttle Lever Pin
24 O-Ring
25 O-Ring
26 O-Ring
27 O-Ring
28 O-Ring
29 Washer
30 Spring Washer

SKU 99792 For technical questions, please call 1-800-444-3353. Page 16
ASSEMBLY DIAGRAM

SKU 99792 For technical questions, please call 1-800-444-3353. Page 17
Record Product’s Serial Number Here:
Note: If product has no serial number, record month and year of purchase instead.
Note: Some parts are listed and shown for illustration purposes only, and are not avail-
able individually as replacement parts.
90 Day Warranty
Harbor Freight Tools Co. makes every effort to assure that its products meet
high quality and durability standards, and warrants to the original purchaser that
this product is free from defects in materials and workmanship for the period
of 90 days from the date of purchase. This warranty does not apply to damage
due directly or indirectly, to misuse, abuse, negligence or accidents, repairs or
alterations outside our facilities, criminal activity, improper installation, normal
wear and tear, or to lack of maintenance. We shall in no event be liable for
death, injuries to persons or property, or for incidental, contingent, special or
consequential damages arising from the use of our product. Some states do
not allow the exclusion or limitation of incidental or consequential damages, so
the above limitation of exclusion may not apply to you. THIS WARRANTY IS
EXPRESSLY IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS.
To take advantage of this warranty, the product or part must be returned to us
with transportation charges prepaid. Proof of purchase date and an explanation
of the complaint must accompany the merchandise. If our inspection veries the
defect, we will either repair or replace the product at our election or we may elect
to refund the purchase price if we cannot readily and quickly provide you with a
replacement. We will return repaired products at our expense, but if we determine
there is no defect, or that the defect resulted from causes not within the scope of
our warranty, then you must bear the cost of returning the product.
This warranty gives you specic legal rights and you may also have other rights
which vary from state to state.